DE2909502A1 - MAGNETIC TAPE HOLDER OR CASSETTE - Google Patents

Description

29U9502

Magnetic tape holder or cassette

The invention relates to a magnetic tape reel holder or a cassette for so-called cassette tape recorders.

Holders or cassettes of the type mentioned are known and it is also known how much their use has increased has, since they can be used in magnetic recorders of particularly small dimensions, which are known as cassette recorders designated.

The holder or cassette essentially consists of two plastic profile plates, which by mutual engagement are connected to one another by projections and corresponding recesses at the corners of the plates. she form a holder closed on three sides, in which the recorded or to be recorded magnetic tape reel is housed is, and on the fourth side of which a suitable passage is left free for the magnetic tape, so that it can pass between the magnetic heads of the recorder

The holder is provided with two central holes penetrating the plates perpendicular to their plane which protrude through the drive shafts of the recorder.

It is known that in the manufacture of a holder or cassette of this type, the main problem therein exists that a smooth run or passage of the magnetic tape is achieved in such a way that it is

2 ^ 09502

let and the inlet of the holder always in the same position passes through, thereby ensuring the best quality of playback and / or recording because the magnetic tape always occupies the same position between the magnetic heads of the recorder.

The described problem is particularly serious because the uneven advance of the magnetic tape Must increase the force required to move it forward, thereby reducing its service life,

In addition, the uneven running of the magnetic tape its edges wear more quickly, with considerable intensity on the inner surface of the Grind along the holder.

The disadvantages mentioned are in addition to the operation at normal drive speed of the magnetic tape especially during the fast winding phase. and unwinding the tape at a considerably increased speed noticeable.

These disadvantages also have a detrimental effect Beginning of winding or unwinding the magnetic tape, even at normal recording or playback speeds, because the end of the full, larger diameter bobbin is subjected to considerable tension. This is particularly the case when the entire magnetic tape reel is due to a previous uneven winding process is not correctly positioned on the respective peg - Finally, it should be noted that the magnetic tape moves away from its correct position more often the moment it expires from the full spool. In fact, it takes away the effects of the vibrations

29US502

the drive shafts from which it is very far away, more sensitive and offers the guide element at the exit of the holder a minimal contact surface.

The object of the invention is to design a holder or a cassette of the type mentioned so that the disadvantages outlined are overcome. The magnetic tape reel holder , consisting of two profile plates in which two central holes are formed for the passage of the recorder drive shafts, the plates delimiting an outer passage for the magnetic tape on one side and guide elements for the inside of the holder at the ends of this passage Magnetic tape are provided, is characterized in that the shape of the guide piece for the magnetic tape on the side on which the magnetic tape slides, is designed substantially in the form of a spiral arc, that the inner surface of each plate around the holes for the passage of the recorder drive shafts is designed substantially concave, and that on the inner surface of each plate two substantially circular walls are arranged, each coaxially aligned with one of the holes for the passage of the recorder drive shafts.

The features of the magnetic tape reel holders according to the invention will appear more clearly from the following description of embodiments illustrated in the drawing. It shows:

Fig. 1 is a view of the inside of one of the two profile plates,

Fig. 2 is a view of the inside of the second profile plate,

Fig. 3 is a plan view of a first embodiment the guide pieces for the magnetic tape on an enlarged scale as a detail,

9098 * 0/057?

FIG. 4 shows a view of the guide piece according to FIG. 3 along the line IV-IV of Figure 3,

Fig. 5 is a plan view of a further embodiment of the guide pieces for the magnetic tape on an enlarged scale as a detail,

Fig. 6 is a view of this embodiment along the Line VI-VI of Figure 5,

7 shows a cross section of a further embodiment the guide pieces,

8 shows a plan view of the part of the guide piece arranged on the second plastic profile plate,

FIG. 9 shows a cross section of the guide piece along the line IX-IX in FIG. 8,

10 shows a view along the section line X-X of the FIG Figure 1 plate shown,

11 is a view along the section line XI-XI of plate shown in Figure 2,

12 is a view along the section line XII-XII
the plate shown in Figure 1, and

13 shows a view along the section line XIII-XIII the plate shown in Figure 2.

FIGS. 1 and 2 show that the magnetic tape reel holder according to the invention consists of two essentially rectangular plastic plates 1, 1a, each of which has a standing or bent lip 2 on three sides, by means of which the holder is closed and sealed. For the mutual fixed connection of the two panels
1, 1a serve snap-lock-like pins 3 at the corners of the plate 1 and corresponding sockets 3a on the

Corners of the plate 1a. On the remaining side of the disks 1, 1a, an outer passage 4 is provided in the usual way for the passage of the magnetic tape N, shown in broken lines, between the magnetic heads of the recorder.

O384O /

2903502

On the inner wall of each disk 1 are a plurality of radial ribs 5 around each hole 6 for the passage of the recorder drive shafts arranged. The ribs 5 can advantageously be designed as in the German patent application P27 35 992.8 dated August 10, 1977 by the same applicant is described and claimed.

Each plate 1 or 1a is equipped on the inside with two substantially circular walls 7, which to the holes 6 are coaxial, and the height of which is slightly less than that of the bent lip 2. The walls 7 are advantageously formed in one piece with the plates 1 immediately during the molding process.

In particular, Figures 1 and 2 show that each wall 7 from There are segments, but this is only done to facilitate the molding process - they can also be made in one piece without interruption be designed. The walls 7 also include an additional segment 7a, which is located in the central zone of the plate is on the side of the passage 4.

The walls 7 and the segments 7a, which serve as a reinforcing element for the plates 1, '1 ^a and make them more resistant to mechanical and thermal loads, are also effective as a guide for the magnetic tape reel shown in dashed lines. As a result, when a full spool begins to rotate, it cannot shift, which would cause the tape to run unevenly.

Figures 1 and 3 show that the holder according to the invention on the plate 1 at each end of the passage 4 for the magnetic tape N a guide piece 8 for the magnetic tape N wearing. The guide piece 8 consists of one on the plane of FIG Plate 1 standing mold wall 9 with the curved lip 2 of the plate 1 a passage 10 for the magnetic tape N. limited.

909840/0577

The vertical configuration of the wall 9 is explained below with reference to FIG. In contrast to conventional circular guide pins, the guide piece 8 is elongated against the direction from which the broken-line magnetic tape N arrives at the guide piece 8. In particular, the wall 9 on which the magnetic tape slides has a substantially spiral arc shape. The shape of this shape results from the envelope curve of a series of circular arcs.In particular, the position of each circular arc and its radius of curvature cause the actually achieved shape to approximate the ideal shape, according to which the magnetic tape N always runs tangentially to the guide piece 8 during its run. The number of circular arcs used to represent the shape of the wall 9 determines the degree of accuracy with which the actual shape approximates the ideal shape. In particular, FIG. 3 shows that the contact zone of the magnetic tape N with the guide piece 8 _{is limited in the starting position N 1} corresponding to a full reel, while the mutual contact zone in the position KL corresponding to the completely empty reel occupies practically the entire wall 9. During the unwinding of the tape from the reel, the area of contact between the magnetic tape and the guide piece 8 gradually increases at a _{constant rate from the position N 1 to the position N 1.} In particular in position N ₁ , there is the lowest friction with a corresponding reduction in the driving force. This is particularly advantageous because in this position the magnetic tape is exposed to the maximum driving force, since its end pulled from the reel is at a maximum distance from the drive shaft. Since the contact area between the magnetic tape N and the guide piece 8 is greatest in the position N, there are maximum friction conditions, but this is not harmful to the magnetic tape because the drive

009840/0577

2309502

power to which it is exposed is the smallest. The distance from the end of the magnetic tape coming off the reel N has the smallest distance from the drive shaft. In addition, this situation creates the best management conditions achieved for the magnetic tape.

According to Figures 3 and 4, the wall 9 of the guide piece equipped at its lower part with a base having a sloping wall 9a, which is a further guide for forms the tape so that it does not touch the inner lower surface of the plate 1.

Figures 5 and 6 illustrate another embodiment of the guide piece 8. In this case the guide piece 8, which is shown and described with reference to FIG. 3 at the opposite end of the passage 4 is arranged. This is possible because of the shape of the guide pieces 8 both in the preferred embodiment and in its modification with respect to one between the Holes 6 extending longitudinal axis is the same and symmetrical.

According to Figure 5, the guide piece 8 is provided in this case with a series of smooth troughs 11, which extend over extend its entire height. In the illustrated embodiment, three troughs are provided, but can be it more or less. The shape of the troughs, i.e. the shape of their cross-section, advantageously corresponds to that in the German patent application P 28 09 972.1 of March 8, 1978 described and claimed lines. Even in this case the cross-section of each trough 11 can be advantageous be elliptical, but also give satisfactory results with a circular cross-section.

Through the trough 11, the contact surface between the Magnetic tape N and the guide piece 8 considerably reduced.

909840/057

In this way, the driving force of the tape N is decreased and, in addition, the abrasion of the magnetic tape is decreased on the guide piece 8 while reducing the electrostatic charges. As already Explained in the aforementioned patent application, the troughs 11 cause the generation of on their inside Convection currents that facilitate the avoidance of electrostatic ■ charging.

The contact area between the magnetic tape N and the Guide piece 8 consists essentially of the projections 12 between the troughs 11, the width of which is very limited is. The shape of each protrusion 12 is composed of a segment of the foregoing with reference to FIG preferred embodiment described shape. Everyone Projection 12 therefore consists of a segment of a spiral arc.

The considerations for this embodiment are the same as for the basic embodiment mentioned, ie that the belt N always runs tangentially to the guide piece 8 _{at every moment of its running movement from its position N 1} to its position N _2.

The wall 9 of the guide piece 8 extends at the two drawn embodiments on the opposite side of the passage 10 in a wall 13 which the has the same function as walls 7 and 7a.

From Figure 6, which shows a cross section of the modified embodiment of the guide piece 8 shows, it can be seen that in this embodiment, the guide piece is provided with a base which has an inclined wall 9a, whose Task is the same as in the first example.

909840/0 5

Figures 4 and 6 show that the wall 9 in both Cases is just. Another design of the wall 9 is shown in FIG. 7. Here, the wall 9 has an outer surface 9b provided, which is convexly curved substantially in the middle and is also for the correct guidance of the magnetic tape N is suitable. The outer surface 9 allows a centering of the magnetic tape in the transverse direction during its course.

The described training of the guide piece can this itself must be arranged in the vicinity of the end portion of the curved lip 2, i.e. in the run-out zone of the magnetic tape N. In the conventional holders, the guide pins are arranged differently, in particular further offset against the inside of the holder.

The illustrated position of the guide piece 8 is not to be regarded as an exclusive option because it is dependent of the respective requirements, the guide piece can be moved against the inside of the holder without that the scope of the invention is left. Also the shape of the curve according to which the wall 9 is constructed, and which preferably has a spiral curve, can be modified somewhat.

Figures 8 and 9 show a part 8a protruding from the bottom surface of the plate 1a and part of the guide piece 8 forms when the two plates 1, 1a are attached to one another. Part 8a consists of one approach 14 with an inclined surface 15, the height of which is essentially that of the base 9a of the guide piece 8 corresponds (Figure 9). When the plates 1 and 1a are connected to one another, a guide piece 8 is produced in this way with a substantially flat or convex surface, at the ends of which there are two inclined surfaces, one

Limit the groove on which the magnetic tape runs.

In particular, Figure 8 shows that the shape of the part 8a in the two preferred embodiments according to FIG 8 and a modification not shown with that of the wall 9 is identical.

According to Figures 10 to 13, the inner surfaces of the profile * - plates 1 and 1a around the holes 6 are substantially concave. In the embodiment shown, the Bottom surface 16 of the plates 1, 1 a in the one surrounding the holes 6 Zone conical, and therefore the thickness of the plates 1,1a increases from the bent lip 2 in the direction of the holes 6 from.

A significant improvement in drive conditions of the tape results from the fact that it is guided more stably under less favorable conditions, i.e. when the spool is full will. With these conditions, the outer part of the spool can easily be moved with the conventional holder, because it is more exposed to the possible vibrations of the drive shafts. The conical shape of the bottom of the Panels 1, 1a allows a reduction in space, in which the coil is housed, in the zone in the vicinity their outer edge.

Changed embodiments and modifications of the magnetic tape holder or the cassette according to the invention are possible without departing from the scope of the invention.

909840/0 5 7

Claims (1)

SCHÖNWALD EiSHOLD -.FUES- VON KREISLER
FROM KREISLER KELLER SELTING WERNER PATENT LAWYERS Applicant : Dr.-Ing. by Kreislert 1973 _m " _m " _{,, T,,} . , .., Dr.-Ing. K. Schönwald, Cologne START S.r.l. (Italian limited Dr.-Ing.K.W. Eishold, Bad Soden partnership) Dr. j. R Fues, Cologne ■, _T · _n ry r Dipl.-Chem. Alek von Kreisler, Cologne Via LOmO, Zt> Dipl.-Chem. Carola Keller, Cologne ROVELLASCA (Como) Italy Dipf.-Ing.G.Setting, Cologne Dr. H.-K. Werner, Cologne Sg-DB / my _; March 9, 1979 DEICHMANNHAUS AT THE MAIN RAILWAY STATION D-5000 COLOGNE 1 EXPECTATIONS (Iy magnetic tape holder or cassette for so-called cassette tape recorder, consisting of two together attached profile plates, in which two central holes for the passage of the recorder drive shafts. forms are, wherein the plates limit an outer passage for the magnetic tape on one side and to the Ends of this passage are provided on the inside of the holder guide pieces for the magnetic tape, characterized in that the shape of the guide piece (8) for the magnetic tape (N) on the side on which the magnetic tape slides in is designed essentially in the form of a spiral arc that the inner lower surface (16) of each plate (1,1a) the holes (6) for the passage of the recorder drive shafts around are substantially concave, and that on the inner surface of each plate (1,1a) two substantially circular walls (7) are arranged, each are aligned coaxially with one of the holes (6) for the passage of the recorder drive shafts. 909840/0 * 77 : 02? L! Π1041 Te! «· 8882307 dopa d - Telegrammr DompatertfKälrr 2. Holder according to claim 1, characterized in that g e mark e i c h η e t that the shape of each guide piece (8) is derived from the envelope curve of a series of Arcs results, the position and radius of curvature is chosen so that the magnetic tape (N) in every moment meets its lead tangentially against the guide piece ■ (8). 3. Holder according to claims 1 or 2, characterized in that each guide _{piece c} (8) has a series of troughs (11) which extend over its entire height and limit projections (12), the shape of which each consists of a segment of the Spiral arch. 4. Holder according to claim 1, characterized g e mark eichnet that each guide piece (8) at its lower part has a base with a sloping wall (9a). 5. Holder according to claim 1, characterized in that the plate (1 a) in one the position of the guide pieces (8) corresponding zone has a protruding part (8a) whose shape corresponds to that of the guide pieces (8). 6. Holder according to claims 1 and 5, characterized in that the projecting part (8a) has an inclined surface (15). 7. Holder according to claim 1, characterized in that that the contact surface of the guide pieces (8) with the magnetic tape (N) is flat is. 9 03840 / 0B7 8. Holder according to claim 1, characterized in that the contact surface the guide piece (8) with the magnetic tape (N) has an essentially central convex curvature. 9. Holder according to claim 1, characterized in that the inner surface (16) of the Profile plates (1,1a) designed essentially conically around the holes (6) for the passage of the recorder drive shafts is.